1. Field of the Invention
The present invention relates to switches, and more particularly, to matrix switches for RF applications.
2. Description of Related Art
Matrix switches have a plurality of inputs and a plurality of outputs in which any one input can be connected to any one output. Consequently, matrix switches are very useful devices for routing signals. For switching radio frequency (RF) signals, one prior matrix switch comprises a plurality of single pole, multiple throw input switches which are coupled by cables to a plurality of single pole, multiple throw output switches. For example, a 4.times.4 switch matrix has four inputs and four outputs in which any one of the four inputs can be connected to any one of the four outputs. For RF applications, it is preferable that any one input not be connected to more than one output and vice-versa. In one design, each of the four inputs is connected to one of four single pole, four throw input switches. Each output of the matrix switch is similarly connected to one of four single pole, four throw output switches. Each single pole, four throw input switch has four reed conductors, each reed conductor for selectively connecting the switch input terminal to one of four output terminals. Each output terminal of each input switch is connected by coaxial cable to one of four input terminals of one of the four output switches. Each output switch has four reed conductors for coupling one of the four input terminals to the output terminal of the output switch. Thus, a 4.times.4 matrix switch can have as many as thirty-two (32) reed conductors (eight (8) switches, four (4) reed conductors per switch) and sixteen (16) coaxial cables connecting the sixteen (16) outputs of the four (4) input switches to the sixteen (16) inputs of the four (4) output switches. It is readily seen that such a matrix switch is quite complicated and therefore costly and subject to reliability problems. Moreover, it is also quite bulky and heavy which can be very disadvantageous in weight sensitive environments such as those found aboard aircraft. Still further, each of the 32 reed conductors may require a separate solenoid to actuate the reed conductors. This further adds to the weight and expense of the switch.